The impact of drought conditions can be reduced with the use of wetting agents, which can reduce soil hydrophobicity, and increase water infiltration throughout the root–zone.

As a rule, wetting agents are designed for use on a PREVENTIVE basis, usually on a monthly schedule.

They may be beneficial not only to putting greens, but also to fairways.

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2. Fertilization Practices

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Nitrogen fertilization ―

An imbalanced fertilization will increase annual bluegrass’s susceptibility to Curvularia.

In particular, EXCESSIVE LEVELS OF NITROGEN will aggravate Curvularia attacks.

However, this warning to avoid excessive nitrogen use during the summer months is NOT meant to imply that nitrogen use should be suspended entirely.

The ADEQUATE level for annual bluegrass should still be provided at the usual rate of one pound of available nitrogen per one thousand square feet per growing month.

It should also be noted that any program that delivers INADEQUATE spring and fall nitrogen fertilization will decrease turf tolerance to heat and drought stress, thus predisposing it to Curvularia outbreaks.

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Quickly available nitrogen sources ―

As a preventive measure against Curvularia, quickly–available sources of nitrogen should be avoided.

This is because the use of quickly–available sources can produce « surges of growth » that will make the turf susceptible to Curvularia.

The rate of release of these sources usually varies from one to three weeks, depending on the product used.

For example, the estimated period of complete nitrogen release for soluble urea ( 46–0–0 ) is two to three weeks.

Urea is a component used in both granular and liquid fertilizers.

To minimize the rate at which urea is made available to turf, the fertilizer used must contain a HIGH PERCENTAGE OF SLOW–RELEASE NITROGEN.

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Slow–release nitrogen sources ―

During the summer months, any granular fertilization program should include a HIGH LEVEL of slow–release nitrogen in every application.

The criteria for selecting slow–release nitrogen sources must be stringent.

It is recommended that these sources release, at most, fifty to fifty–five per cent of their nitrogen within the first four weeks.

This rate of release can be found in organic nitrogen, polymer–coated ureas, and urea–formaldehyde products.

Moreover, when choosing a fertilizer mixture for fairways, its composition must be of at least seventy–five per cent slow–release nitrogen.

For putting greens, one–hundred per cent is preferred.

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Liquid nitrogen sources ―

During the summer months, using a liquid fertilizer program may be problematic.

Even so–called slow–release sources of liquid nitrogen may contain extremely high levels of urea.

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Potassium fertilization ―

The benefits of potassium to turfgrass growth include improved hardiness against extremes, such as heat and drought, and improved resistance to diseases, including Curvularia.

Applying potassium is NOT effective once summer stress or disease occurs.

Potassium must be used PREVENTIVELY.

The spring use of potassium is a means of preparing turf to better resist HEAT and DROUGHT stress, the two factors that will predispose annual bluegrass to infections of Curvularia.

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Nitrogen–to–potassium ratio ―

To ensure the highest degree of heat and drought resistance, some turf managers select fertilizers with a nitrogen–to–potassium ( N–K20 ) ratio of 1–to–1.

Others prefer a ratio based upon soil test results, or employ more CONVENTIONAL ratios, such as 2–to–1, or 3–to–1.

Some experts more precisely recommend the use of 1–to–1 ratios for high–sand soils and high–leaching conditions. Such conditions are usually found on putting greens.

Moreover, when the annual application of nitrogen exceeds 6 pounds per 1000 square feet, it is advised to use ratios of 1–to–0.75 or 1–to–0.50.

For 3 to 6 pounds of nitrogen per 1000 square feet per year, a ratio of 1–to–1 is advocated.

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3. Herbicide Applications

Research has shown that the use of herbicides, such as 2,4–D, mecoprop, and dicamba may stimulate Bipolaris and Drechslera development.

Although no such research has been done with Curvularia, it is a safe assumption that this organism is also activated by these herbicides.

Therefore, the use of broad–leaved weed control products should be AVOIDED during the summer months.

If the use of such weed controls is deemed necessary, small areas should be sprayed as « tests » before implementing an overall herbicide program.

Moreover, areas that have historically been infected with Curvularia should be avoided altogether until fall.

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4. Leaf Wetness and Irrigation Practices

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Poor air circulation ―

Prolonged exposure of grass leaves to moisture, in combination with high temperatures, creates an ideal environment for Curvularia infection. High humidity weather and poor air circulation will result in moisture remaining on turf leaves for extended periods.

Air circulation may be impeded by the presence of NUMEROUS LARGE TREES very close to the turf area.

Therefore, large trees should NOT be planted within one–hundred feet of the perimeter of golf course putting greens. Such existing trees may need to be removed.

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Mimicking symptoms of drought ―

It is often difficult to distinguish Curvularia from drought. In both cases, the turf appears thin and weak, and seems to be suffering from lack of water.

However, diseased turf will NOT recover with adequate or increased irrigation.

In fact, the opposite is likely to occur. Increased and untimely irrigation will aggravate the disease.

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Irrigation practices ―

Irrigating late in the day tends to increase the incidence of Curvularia.

So too will light and frequent drenching.

Therefore, irrigation should be done early in the day, rather than late at night, to decrease the risk of Curvularia.

During hot weather, irrigation quantities should be MISERLY, BUT SUFFICIENT.

Moisture deficiency can be determined by the feel and appearance of the soil, or by the appearance of the turf.

For instance, a bluish leaf colour and drooping foliage indicate that moisture stress has been reached.

Obviously, turf should be irrigated just prior to this point; otherwise, wilting injury may occur.

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5. Mis–diagnosis of Diseases and Insects

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Problems of discernment from other diseases ―

Misidentification of a disease can lead to IMPROPER corrective action.

The following summer turf diseases produce symptoms that are similar to Curvularia ―

( 1 ) Anthracnose Leaf Blight.

( 2 ) Black Layer.

( 3 ) Summer Patch.

In fact, Curvularia will often infect annual bluegrass IN UNISON with Anthracnose Blight and Summer Patch.

This is why diagnosis of Curvularia and Summer Patch should always be performed with a MICROSCOPE.

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Problems of discernment from insect pests ―

Annual bluegrass will be more susceptible to Curvularia with exposure not only to drought stress, but also to insect attack.

In fact, it may be difficult to distinguish Curvularia infection from drought injury or insect damage.

In the months of June, July, and August, two white grub larvae insects cause symptoms that are SIMILAR to Curvularia by chewing away at the roots of turf plants ―

( 1 ) Annual Bluegrass Weevil.

( 2 ) Black Turfgrass Ataenius.

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6. Mowing Height

Obviously, the effect of any disease that begins by attacking leaves will be more devastating as mowing length is SHORTER.

When Curvularia is active, the mowing height must be raised to the MAXIMUM POSSIBLE LEVEL.

Short and frequent cutting must be stopped.

Additionally, turf that is subject to obvious heat and drought stress should NOT be mowed, especially not in the afternoon.

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7. Soil Compaction and Mechanical Activities

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Traffic ―

Annual bluegrass will be more prone to infections of Curvularia when its leaves are subjected to OPEN WOUNDS.

The frequent use of vehicles on turf, particularly during hot and dry weather, creates such avenues for disease attack. Maintenance equipment, and even golf cars, may have to be RESTRICTED from operating on turf areas.

Full prohibition may become an absolute necessity during hot and dry summer afternoons, when day–time temperatures peak.

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Mechanical interventions ―

During the summer months, the UNTIMELY implementation of mechanical cultural practices may add unnecessarily to heat and drought stress, thus increasing the risks of Curvularia infection on annual bluegrass.

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Mechanical interventions that constitute a HIGH–RISK injury include ―

( 1 ) core aeration,

( 2 ) heavy vehicle use,

( 3 ) soil topdressing,

( 4 ) triplex greens mowing, and

( 5 ) verti–cutting.

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Mechanical interventions that represent a LOW–RISK injury include ―

( 1 ) arrow–head aeration on fairways ( i.e. Aer–Way ),

( 2 ) conditioning of golf course putting greens with groomers,

( 3 ) light–weight fairway mowing,

( 4 ) manual greens mowing,

( 5 ) slicing aeration,

( 6 ) solid–tine aeration of greens, and

( 7 ) spiking aeration.

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Aeration practices ―

An INADEQUATE core aeration program in the preceding spring and fall, will WEAKEN turf resistance to heat and drought stress.

Likewise, previously INADEQUATE spring and fall core aeration will also render turf LESS ABLE to tolerate summer heat and drought stress.

Such stress can predispose turf to Curvularia infections on annual bluegrass.

Force Of Nature presents THE WHOLE TRUTH FROM AN INDEPENDENT PERSPECTIVE from National Organization Responding Against Huje that seek to harm or misinform the Green Space Industry (NORAHG). It is a series of Reports destined for the Green Space Industry, the Environmental Terror Movement, Governments, and the Media, nationwide across Canada, the United States, and overseas. This Report has been developed for the education and entertainment of the reader by providing TECHNICAL INFORMATION WITH COMMENTARY. The neutrality of the Report might be disputed.

The information presented in this Report is for preliminary planning only. Before making a final decision, the turf manager is expected to obtain trusted expert advice from extension specialists, local distributors and/or agronomists. All decisions must take into account the prevailing growing conditions, the time of year, and the established management practices

All products mentioned in this Report should be used in accordance with the manufacturer’s directions, and according to provincial, state, or federal law. For the official advantages, benefits, features, precautions, and restrictions concerning any product, the turf manager must rely only on the information furnished by the manufacturer. The mention of trade names does not constitute a guarantee or a warranty.

All information, excerpts, and pictures contained in this Report were found somewhere on the Internet, and may be considered in the public domain, serving one of the following purposes ― archive, education, promotion, publicity, or press release. Force Of Nature is TOTALLY INDEPENDENT of any trade association or business operating within the Green Space Industry. Don’t thank us. It’s a public service. And we are glad to do it.

Force Of Nature is the brainchild of William H Gathercole and his entourage. Mr Gathercole is a principal founder of the Modern Professional Lawn Care Industry in both Ontario and Quebec. He holds a degree in Horticulture from the University of Guelph, and another pure and applied science degree from McGill University. He has worked in virtually all aspects of the Green Space Industry, including golf, professional lawn care, and distribution. Mr Gathercole has supervised, consulted, programmed, and/or overseen the successful execution of hundreds of thousands of management operations in the urban landscape. He has trained, instructed, and advised thousands of turf managers and technicians. Mr Gathercole has also been an agricultural agronomist. Mr Gathercole is personally credited for crafting the Exception Status that has allowed the Golf Industry to avoid being subjected to the prohibition of pest control products. He is also the creator of the signs that are now used for posting after application. Mr Gathercole is now retired from Force Of Nature, although his name continues to appear as the founder.